A 55-year-old woman presents with fatigue and lymphadenopathy. Bone marrow biopsy shows 70% lymphocytes with a proliferation center pattern. Flow cytometry: CD19+, CD5+, CD23+, ZAP-70+. Cytogenetics show del(17p). This cytogenetic finding in CLL is associated with:
- A Better prognosis than no cytogenetic abnormality
- B Sensitivity to standard chlorambucil chemotherapy
- C The worst prognosis due to loss of TP53 ✓
- D Transformation risk to follicular lymphoma
Correct answer: C. The worst prognosis due to loss of TP53
Explanation
Del(17p) in CLL involves loss of the TP53 tumor suppressor gene and confers the worst prognosis among CLL cytogenetic subgroups: rapid progression, resistance to standard chemoimmunotherapy (fludarabine, chlorambucil), and short survival. These patients require BTK inhibitor (ibrutinib) or venetoclax-based therapy. Del(13q) alone confers the best prognosis; del(11q) and trisomy 12 have intermediate prognosis; Richter transformation is to DLBCL, not follicular lymphoma.
Reference: Robbins & Cotran Pathologic Basis of Disease, 10th ed.
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